The Department of Orthopedics and Replantation Research Laboratory of the Sixth People’s Hospital of Shanghai was at the forefront of technical innovation and development of limb and digital replantation and early microsurgery in the mid-1960s, half a century ago. This was a period when the entirety of China was isolated from the rest of the world, with revolutionary movements spreading over the entire country. Almost unbelievably, the early development of microsurgery took place during this period, unknown to the rest of the world. As a member of the earliest research team in the replantation laboratory and a member of the surgical team in the department, the author recollects some little-known facts dating back half a century that led to now-familiar techniques in microsurgery.
Anastomosing a greater number of veins is necessary in digital and arm replantation
Because swelling of the replanted arm was a major problem in the first cases in this unit, multiple small incisions were made to drain the venous blood. From the mid-1960s, attempts were routinely made to connect more veins than arteries in replanting an arm. Consequently, fewer replantation failures were caused by limb swelling. It became a rule to always connect more veins than arteries in limb replantation; such a rule was applied to digital replantation as well.
The ischemia time of severed limbs: cold preservation
Prolonging the survival time of amputated limbs or digits was a central concern of the team at that time, because patients with arm amputations often could not be transported to Shanghai from far away in a timely fashion. There were very few centers in China capable of performing limb replantation at that time. Canine experiments were carried out to test whether preservation of the amputated limb at 0°C to 4°C substantially prolonged survival of a severed limb ( Figs. 1 and 2 ). It was found that without cold preservation, the canine limb could not be successfully replanted after 10 hours of ischemia. In contrast, cold preservation of the amputated canine limbs doubled and tripled the time of ischemia allowable before a successful limb replantation. The longest time for replantation for such an amputated canine limb reached 108 hours ( Fig. 3 ). It was thought that if cold preservation could extend the ischemia time to over 100 hours (which translates to an entire day for a human limb), there was no need to seek further solutions: cold preservation should buy enough time for any patient to be transported to a replantation center.
A funny story relates to figuring out how to achieve cold preservation in some rural areas. In 1965, there was a phone call from a mountainous area of west Zhejiang about a farmer whose hand had been severed. How to preserve the hand for the long journey necessary? More than 100 popsicles were placed around the hand, which was wrapped in a plastic bag. After transfer to our unit 17 hours later, replantation was successful because of the cold preservation by the popsicles!
The ischemia time of severed limbs: cold preservation
Prolonging the survival time of amputated limbs or digits was a central concern of the team at that time, because patients with arm amputations often could not be transported to Shanghai from far away in a timely fashion. There were very few centers in China capable of performing limb replantation at that time. Canine experiments were carried out to test whether preservation of the amputated limb at 0°C to 4°C substantially prolonged survival of a severed limb ( Figs. 1 and 2 ). It was found that without cold preservation, the canine limb could not be successfully replanted after 10 hours of ischemia. In contrast, cold preservation of the amputated canine limbs doubled and tripled the time of ischemia allowable before a successful limb replantation. The longest time for replantation for such an amputated canine limb reached 108 hours ( Fig. 3 ). It was thought that if cold preservation could extend the ischemia time to over 100 hours (which translates to an entire day for a human limb), there was no need to seek further solutions: cold preservation should buy enough time for any patient to be transported to a replantation center.
A funny story relates to figuring out how to achieve cold preservation in some rural areas. In 1965, there was a phone call from a mountainous area of west Zhejiang about a farmer whose hand had been severed. How to preserve the hand for the long journey necessary? More than 100 popsicles were placed around the hand, which was wrapped in a plastic bag. After transfer to our unit 17 hours later, replantation was successful because of the cold preservation by the popsicles!
Rabbit ear as a model for experimenting microsurgery
In those early days, the best model for practicing vascular anastomosis was unclear. That was when rabbit ears came into use for practicing and researching surgical replantation ( Fig. 4 ). Vascular diameters in the rabbit ear are similar to those of vessels in the fingers, and because ear tissue is thin, vascular flow could be easily visualized against lighting. Exercise of replantation in such a rabbit ear model formed the foundation for clinical success in digital replantation in 1966 and later free vascularized muscle transfer in 1973.
